1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
|
use crate::regex::Class;
use super::{Match, Pattern, RegexEngine};
fn empty_match() -> Option<Match> {
Some(Match {
submatches: [].into(),
})
}
#[derive(Debug)]
pub struct Anything;
#[derive(Debug, Clone)]
pub struct NotASimpleWildcard;
impl RegexEngine for Anything {
type CompileError = NotASimpleWildcard;
fn compile(pat: Pattern) -> Result<Self, Self::CompileError> {
match pat {
Pattern::Rep(pat, 0, None, _) => match *pat {
Pattern::CharacterClass(Class::Everything) => Ok(Anything),
_ => Err(NotASimpleWildcard),
},
Pattern::Concat(pats) | Pattern::Alt(pats) => {
if !pats.is_empty() && pats.into_iter().all(|p| Anything::compile(p).is_ok()) {
Ok(Anything)
} else {
Err(NotASimpleWildcard)
}
}
_ => Err(NotASimpleWildcard),
}
}
fn run(&self, _input: &[u8]) -> Option<Match> {
empty_match()
}
}
#[derive(Debug)]
pub struct Nothing;
#[derive(Debug, Clone)]
pub struct NotASimpleNothing;
impl RegexEngine for Nothing {
type CompileError = NotASimpleNothing;
fn compile(pat: Pattern) -> Result<Self, Self::CompileError> {
match pat {
Pattern::Range(a, b) if a > b => Ok(Nothing),
Pattern::CharacterClass(Class::Nothing) => Ok(Nothing),
Pattern::Alt(pats) => {
let all_impossible = pats.into_iter().map(Self::compile).all(|p| p.is_ok());
if all_impossible {
Ok(Nothing)
} else {
Err(NotASimpleNothing)
}
}
Pattern::Concat(pats) => {
if let Some(pat) = pats.into_iter().next() {
Self::compile(pat)
} else {
Err(NotASimpleNothing)
}
}
Pattern::Rep(_, x, Some(y), _) if y < x => Ok(Nothing),
Pattern::Rep(_, 0, None, _) => Err(NotASimpleNothing),
Pattern::Rep(pat, _gt_0, _, _) => Self::compile(*pat),
Pattern::Submatch(pat) => Self::compile(*pat),
_ => Err(NotASimpleNothing),
}
}
fn run(&self, _input: &[u8]) -> Option<Match> {
None
}
}
#[derive(Debug)]
pub struct Exact {
pub bytes: Vec<u8>,
}
const MEM_LIMIT: usize = 25_000;
#[derive(Debug, Clone)]
pub struct NotSimplyAString;
fn ce(pat: Pattern) -> Option<Vec<u8>> {
match pat {
Pattern::Byte(b) => Some(vec![b]),
Pattern::Concat(patterns) => {
let mut pats = patterns.into_iter().map(ce).collect::<Option<Vec<_>>>()?;
let mut out = Vec::new();
for p in pats.iter_mut() {
out.append(p);
}
Some(out)
}
Pattern::Rep(pat, min, Some(max), _) if min == max => {
if let Some(bytes) = ce(*pat)
&& bytes.len() * (min as usize) < MEM_LIMIT
{
Some(bytes.repeat(min as usize))
} else {
None
}
}
Pattern::Submatch(_) => None, // TODO: submatches could be stored as constant offsets
Pattern::Nothing => Some(Vec::new()),
_ => None,
}
}
impl RegexEngine for Exact {
type CompileError = NotSimplyAString;
fn compile(pat: Pattern) -> Result<Self, Self::CompileError> {
match ce(pat) {
Some(bytes) => Ok(Self { bytes }),
None => Err(NotSimplyAString),
}
}
fn run(&self, input: &[u8]) -> Option<Match> {
if input == self.bytes {
empty_match()
} else {
None
}
}
}
|
